Electrical control apparatus



Aug. 3, 1948. A. E. DODD 2,446,216

ELECTRICAL CONTROL APPARATUS Original Filed July 16, 1945 IN VEN TOR.

Patented Aug. 3, 1948 ELECTRICAL CONTROL APPARATUS Arthur E. Dodd', Edgewood, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Original application July 16, 1945, Serial No. 605,400, new Patent No. 2,436,293, dated Feb ruary 17, 1948. Divided and this application June 19, 1947, Serial No. 755,671

3 Claims. 1

My invention relates to electrical control apparatus, and more particularly to apparatus to effect either a first or a second control function according as a control circuit is supplied with current of positive or negative polarity.

The present application is a division of my copending application for Letters Patent of the United States, Serial No. 605,400, filed July 16, 1945, for Electrical control apparatus, now U. S. Patent 2,436,293, dated February 17, 1948.

A feature of my invention is the provision of electrical control apparatus incorporating novel means to assure a first control function in response to current of normal polarity and a second control function in response to current of reverse polarity, and to effect the second function in the event the apparatus fails to properly respond to current of normal polarity.

Another feature of my invention is the provision of improved electrical control apparatus for obtaining a polar control by the use of neutral relays.

Other features, objects and advantages of my invention will appear as the specification progrosses.

The foregoing features, objects and advantages of my invention are attained by the provision of two direct current neutral relays and a novel circuit arrangement for energizing the relays from a control circuit which at times is deenerglzed and to which circuit at other times current is supplied of either positive or negative polarity. For example, the control circuit may be a line circuit of a railway signal system, a battery being connected to one end of the line circuit through contacts of a pole changer type of controller and signal control relays being connected to the other end of the control circuit.

A first one of the relays of the control apparatus here provided is preferably a direct current neutral relay, the armature of which is biased by its own weight to a first or released position when the relay is deenergized and is attracted to a secnd or picked up position when the relay is energized at either polarity. This first or main relay is connected to the control circuit to be energized and picked up when the current of either polarity is supplied to the circuit and to become deenerg-ized and released when the circuit is deenergized.

A second one of the control relays of the control apparatus is preferably a two winding direct current neutral relay which is provided with a pickup and a stick circuit. The pick-up circuit includes one winding of the relay, a back contact of the first relay and. a current source local to the location of the control apparatus. That is, this local source is ordinarily independent of the current source of the control circuit. The local source is poled for the pick-up circuit to energize the second relay at a. preselected polarity, which by way of illustration I shall assume in the following description to be of positive polarity. The stick circuit for the second relay connects a second winding of the relay to the control circuit for energizing the second relay by the control circuit current subsequent to the energization of the first relay to disconnect the local current source. The connection of the stick circuit to the control circult is such that the second relay is energized at its preselected positive polarity if the control circult is supplied with current of positive polarity but not When the control circuit is supplied with current of negative polarity. In this way the energization of the second relay is reversed when the control circuit is supplied with current of negative polarity and such reversal causes the relay to be released as the energization of the relay tends to pass through zero. The second relay once thus released remains deenergized due to the opening of its front contact interposed in its stick circuit until the first relay is released to reclose the pickup circuit. The second relay jointly with the first relay is used to control signal circuits and consequently a first control of such signal circuits can be efiected when current of positive polarity is supplied to the control circuit and the second relay is picked up and a second control of the signal circuits can be effected when the control circuit is supplied with current of negative polarity and the second relay is released.

I shall describe one form of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing a preferred form of apparatus embodying my invention when used to control a railway signal.

It is to be understood that the invention is not limited to the control of a railway signal and this one use serves to illustrate the many places the apparatus is useful.

Referring to the drawing, the reference charac ters LI and L2 designate the two conductors of a control circuit here shown in the form of a line circuit for a railway signal system, and which circuit extends between two signal locations along the railway. At a first location this line circuit is connected to a source of direct current, such as a battery Bl, through contact members Ill and l I of a pole changer type of controller PC. The

arrangement is such that direct current of what I shall call positive polarity is supplied from battery Bl to the line circuit when the controller PC is moved to a first extreme position where its contact members I and II occupy the position shown by the solid lines in the drawing, and current of negative polarity is supplied to the line circuit when the controller is set at a second extreme position and contact members I0 and II occupy the position shown by dotted lines. Furthermore, the controller PC is preferably operable to a mid position where the battery BI is disconnected and the line circuit is deenergized.

At the second location the line circuit is connected to control apparatus which includes a first or main relay HRZ and a second or auxiliary relay HCI. The main relay HRZ is a direct current neutral relay having a winding connected to conductors LI and L2 of the line circuit. Consequently, the relay I-IRZ is energized to pick up a neutral armature to which contact members [4 and I5 are attached to close front contacts 56 and 62, respectively, when the line circuit is supplied with current of either polarity and this armature is released to close back contacts 5 and 51 when the line circuit is deenergized.

The auxiliary relay HC! is a two winding direct current neutral relay and is provided with a pick-up and a stick circuit. The pick-up circuit is supplied with current from a battery LB which is preferably placed at the same location as the control relays. This pick-up circuit can be traced from positive terminal of battery LB through back contact 51 of relay HR2, a first winding 42 of rela HCI and to negative terminal of battery LB. The battery LB is poled for relay HCI to be energized at a preselected polarity by the pick-up circuit, and I shall assume that relay HCI is energized at positive polarity when connected to the battery LB. Relay HCI is also provided with a stick circuit for connecting a second winding M of the relay to the line circuit for energizing the relay by the line circuit current. One side of such stick circuit can be traced from-the left-hand terminal of winding 4| of relay HCi through a resistor 44 and front contact 43 of the relay to conductor LI, and the other side of the stick circuit extends from the righthand terminal of winding 4| to line conductor L2.

The connections of the stick circuit of relay HCI are such that the relay is energized at positive polarity when the line circuit is supplied with current of positive polarity and the relay HCI is energized at negative polarity when the line circuit is supplied with current of negative polarity. Thus, line circuit current of positive polarity energizes the relay HCI at the same polarity as the relay is energized by the local battery LB through the pick-up circuit. Consequently, with relay HCI energized by its pickup circuit, the relay HCI is retained picked up by the line circuit current subsequent to the line circuit being supplied with current of positive polarity and the first relay I-IR2 picked up, the relay HCI being provided with slow release characteristics to retain the relay picked up during the transfer period of the contacts of relay HRZ. However, the energization of relay HCI is reversed subsequent to the picking up of relay HRZ when current of negative polarity is supplied to the line circuit, and such reversal of the energization of relay HCI causes the relay to be released as its energization tends to pass through zero. With relay HCI once released opening its stick front contact 43 the relay remains released until relay HRZ is released to reclose the pick-up circuit. In other words, relay 1-10 I is retained picked up in response to line circuit current of positive polarity and is held released in response to line circuit current of negative polarity.

The apparatus also includes a slow release repeater relay HP for the relay I-IRZ and which repeater relay is energized through an obvious circuit including front contact 56 of relay I-IRZ.

The control relays jointly control a railway signal SI, here shown in the form of a color light signal.

In describing the operation of the apparatus I shall first assume that the line circuit is deenergized due to the controller PC being set at its mid position to disconnect battery Bl. With the line circuit deenergized the main relay H552 and in turn its repeater relay I-IP are deenergized, and with relays HRZ and HP released closing back contacts 55 and 55, respectively, a signal circuit is completed for a lamp R of the signal SI and current is supplied from a suitable source the terminals of which are designated B and C, to the lamp R to illuminate the lamp for the signal to display a stop signal indication.

I shall next assume that the controller PC is set at its first extreme position where the contact members H] and H occupy the full line position and current of positive polarityis supplied to the line circuit. The main relay I-IRZ is now energized to pick up its neutral armature. With relay HRZ picked up, the auxiliary relay HCl is switched from battery LB to the line circuit and the relay HCI is retained picked up by the line circuit current because the line circuit current now energizes the rela HCI at the same polarity as the relay is energized by battery LB through the pick-up circuit. The relay HP is also picked up due to the picking up of the main relay HR2. Under this condition of the control relays a signal circuit extends from terminal B through front contact 62 of relay HRZ, front contact 63 of relay HP, front contact 60 of relay HCI and lamp G of signal SI to terminal C, and the lamp G is illuminated for signal SI to display a clear signal indication. That is to say, the signal SI displays a clear signal indication in response to line circuit current of positive polarity.

In the event the controller PC is moved to its second extreme position, that is, to the dotted line position, and current of negative polarity is supplied to the line circuit, the relay HRZ is energized to pick up its neutral armature the.

same as before.

The energization of the stick or holding windil'lg 4| of relay HCI is now of negative polarity and reverse to the energization of the pick-up winding 42 by battery LB. Such reversal of the energization of relay HCI causes the relay to release as the energization tends to pass through zero. With relay HCI once released it then remains released due to the opening of front contact 43. A signal circuit is now formed from terminal B through front contact 62 of relay HRZ, front contact 53 of relay HP, back contact 6| of relay HCI and lamp Y to terminal C, and that lamp is illuminated for signal SI to display an approach signal indication in response to line circuit current of negative polarity.

Apparatus such as heredisclosed has the advantages that a first function is effected in response to current of one polarity and a second function is effected in response to current of the .lso, the apparatus is comparatively simple and iexpensiveand can be applied to present systems 3 provide polar control.

Although I have herein shown and described ut one form of electrical control apparatus emodying my invention, it is understood that var- 3115 changes and modifications may be made herein within the scope of the appended claims without departing from the spirit and scope of my nvention.

Having thus described my invention, what I :laim is:

1. In combination, a control circuit supplied with direct current of normal or reverse polarity recording as a controller is set at a first or a secand position, a, first neutral relay connected to said control circuit to be energized by the control circuit current, a second neutral relay, a pick-up circuit including a current source independent of the first mentioned current source and a back contact of said first relay connected to a winding of said second relay to energize the second relay at a preselected polarity, a stick circuit including a front contact of the second relay to connect a winding of the second relay to said control circuit and disposed to energize the second relay at said preselected polarity only when the control circuit current is 03f normal polarity whereby said second relay is picked up or is released according as the control circuit current is of normal or reverse polarity, a first signal circuit including a front contact of each of said relays, and a second signal circuit including a front contact of said first relay and a back contact of said second relay.

2. In combination, a line circuit extending between two locations, a. current source at a first one of said locations connected to said line circuit through contacts of a pole changer to supply direct current of normal or reverse polarity according to the position of the pole changer, a first and a second neutral relay at a second one of said locations, said first relay having a winding connected to said line circuit to energize the relay by said current irrespective of its polarity, said secend relay having a pick-up winding connected to a direct current source local to said second location through a back contact of said first relay and a holding winding connected to said line circuit through a front contact of the second relay, said local source poled to energize the second relay at a preselected polarity, said holding winding connected to energize the second relay at said preselected polarity only when the line circuit current is of normal polarity to retain the second relay picked up in response to line circuit current of normal polarity and to release the second relay in response to line circuit current of reverse polarity, and signal circuits selectively controlled by said relays jointly.

3. In combination, a line circuit extending between two locations, 2. current source at a first one of said locations connected to said line circuit through contacts of a pole changer to supply direct current of normal or reverse polarity according to the position of the pole changer, a first, a second and a third neutral relay at a second one of said locations, said first relay connected to said line circuit to be energized and picked up by said line circuit current of either polarity, said second relay having a pick-up winding connected to a direct current source at said second location through a back contact of the first relay and a holding winding connected to the line circuit through a front contact of the second relay, said pick-up winding disposed to energize the second relay at a preselected polarity and said holding winding disposed to energize the second relay at said preselected polarity only when the line circuit current is of positive polarity, said third relay connected to said second location current source through a front contact of the first relay, a first signal circuit including in series a front contact of each of said three relays, a second signal circuit including in series a front contact of each of said first and third relays and a back contact of said second relay, and a third signal circuit including in series a back contact third relays.

ARTHUR E. DODD.

of each of said first and 

